Plasma processing apparatus and method

ABSTRACT

In a plasma processing apparatus in which a radio-frequency power from a radio-frequency power source is supplied to an electrode disposed in a process vessel, to thereby generate, in the process vessel, plasma with which a substrate is processed, a chemical component emitting member which is caused to emit a chemical component necessary for processing the substrate into the process vessel by entrance of ions in the plasma generated in the process vessel is provided in the process vessel in an exposed state, and an impedance varying circuit varying impedance on the chemical component emitting member side of the plasma generated in the process vessel to frequency of the radio-frequency power source is connected to the chemical component emitting member.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.11/691,678, filed Mar. 27, 2007, and contains subject matter related toJapanese Patent Application No. 2006-097446, filed on Mar. 31, 2006 andProvisional Application No. 60/792,317, filed on Apr. 17, 2006, theentire contents of which being incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a plasma processing apparatus and aplasma processing method for processing a substrate with plasmagenerated in a process vessel.

2. Description of the Related Art

In manufacturing processes of, for example, a semiconductor device, aliquid crystal display device, and the like, plasma processing by aplasma processing apparatus is widely used for subjecting asemiconductor wafer to processing such as etching and film formation.Such a plasma processing apparatus includes, in a process vessel, upperand lower electrodes facing each other, and a radio-frequency power issupplied to the lower electrode on which, for example, a substrate isplaced to generate plasma between the lower electrode and the upperelectrode, thereby processing the substrate.

In this plasma processing apparatus, conventionally, in order to enhanceanisotropy of etching and increase etching rate and deposition rate forincreased product yields, various process gases have been used andpressure and temperature of the process gases have been adjusted.Further, the present applicant has disclosed a method to keep highin-plane uniformity of plasma processing by varying impedance on anelectrode side of the plasma generated in the process vessel tofrequency of a radio-frequency power source (see, for example, JapanesePatent Application Laid-open No. 2004-96066).

SUMMARY OF THE INVENTION

For members such as the upper electrode and the lower electrode exposedin the process vessel, a material from which as little contamination aspossible is generated by the plasma generated in the process vessel isused. As a measure for preventing these members from being affected bythe plasma, their sidewall inner surfaces exposed in the process vesselare anodized, for instance. Thus, it has been a conventional tendencythat the emission of components necessary for processing the substratefrom the members exposed in the process vessel is reduced as much aspossible.

It is an object of the present invention to improve plasma processing bycausing a member exposed in a process vessel to emit a componentnecessary for processing a substrate when the substrate is processedwith plasma generated in the process vessel.

To attain the above object, according to the present invention, there isprovided a plasma processing apparatus in which a radio-frequency powerfrom a radio-frequency power source is supplied to at least one of anupper electrode and a lower electrode disposed to vertically face eachother in a process vessel, to thereby generate, in the process vessel,plasma with which a substrate is processed, wherein a chemical componentemitting member which is caused to emit a chemical component necessaryfor processing the substrate into the process vessel by entrance of ionsin the plasma generated in the process vessel is provided in the processvessel in an exposed state, and wherein an impedance varying circuitvarying impedance on the chemical component emitting member side of theplasma generated in the process vessel to frequency of theradio-frequency power source is connected to the chemical componentemitting member.

According to this plasma processing apparatus, the ions in the plasma ismade to enter the chemical component emitting member exposed in theprocess vessel, thereby causing the chemical component emitting memberto emit a chemical component necessary for processing a substrate, sothat it is possible to improve the plasma processing.

In this plasma processing apparatus, the chemical component emittingmember may be disposed on a lower surface of the upper electrode.Alternatively, the chemical component emitting member may be a focusring provided around a periphery of the lower electrode. Alternatively,the chemical component emitting member may be disposed around the plasmagenerated in the process vessel.

The chemical component necessary for processing the substrate is, forexample, oxygen. In this case, the chemical component emitting member ismade of, for example, SiO₂.

Alternatively, the chemical component necessary for processing thesubstrate is, for example, fluorine. In this case, the chemicalcomponent emitting member is made of, for example, fluorocarbon resin.

According to another aspect of the present invention, there is provideda plasma processing method in which a radio-frequency power from aradio-frequency power source is supplied to at least one of an upperelectrode and a lower electrode disposed to vertically face each otherin a process vessel, to thereby generate, in the process vessel, plasmawith which a substrate is processed, wherein a chemical componentemitting member which is caused to emit a chemical component necessaryfor processing the substrate into the process vessel by entrance of ionsin the plasma generated in the process vessel is disposed in the processvessel in an exposed state, and wherein impedance on the chemicalcomponent emitting member side of the plasma generated in the processvessel to frequency of the radio-frequency power source is varied,thereby controlling an emission amount of the component necessary forprocessing the substrate emitted into the process vessel from thechemical component emitting member.

In this plasma processing method, the chemical component necessary forprocessing the substrate is, for example, oxygen. In this case, thechemical component emitting member is made of, for example, SiO₂.Alternatively, the chemical component necessary for processing thesubstrate is, for example, fluorine. In this case, the chemicalcomponent emitting member is made of, for example, fluorocarbon resin.

According to the present invention, by making the ions in the plasmaenter the chemical component emitting member exposed in the processvessel, it is possible for the chemical component emitting member toemit the component necessary for processing the substrate, and by thechemical component emitted in this manner, it is possible to improveperformance of the plasma processing such as etching rate and etchinganisotropy. In this case, by varying impedance on the chemical componentemitting member side of the plasma generated in the process vessel tofrequency of the radio-frequency power source, an amount of the ionsentering the chemical component emitting member from the plasma isadjusted, so that it is possible to easily control an emission amount ofthe chemical component necessary for processing the substrate emittedfrom the chemical component emitting member into the process vessel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a vertical cross-sectional view showing a schematicconstruction of a plasma etching apparatus according to an embodiment ofthe present invention;

FIG. 2 is a circuitry diagram of an impedance varying part;

FIG. 3( a) and FIG. 3( b) are views to explain a case where of a hole isformed in a semiconductor wafer by etching, FIG. 3( a) showing a statewhere etching with high anisotropy is performed and FIG. 3( b) showing astate where the hole has a bowing shape;

FIG. 4 is a circuit diagram showing a modified example of an impedancevarying circuit;

FIG. 5 is a vertical cross-sectional view showing a schematicconstruction of a plasma etching apparatus according to an embodimentwhere a focus ring serves as a chemical component emitting member;

FIG. 6 is a vertical cross-sectional view showing a schematicconstruction of a plasma etching apparatus according to an embodimentwhere a chemical component emitting member is disposed around plasmagenerated in a process vessel;

FIG. 7 is a graph showing etching rate in center and peripheral edgeportions of a semiconductor wafer; and

FIG. 8 is a vertical cross-sectional view showing a schematicconstruction of a plasma etching apparatus according to an embodimentincluding sensors detecting emission intensity (radical density) ofplasma in the center and peripheral edge portions of the semiconductorwafer.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, preferred embodiments of the present invention will bedescribed. FIG. 1 is a vertical cross-sectional view showing a schematicconstruction of a plasma etching apparatus 1 as a plasma processingapparatus according to an embodiment of the present invention. FIG. 2 isa circuitry diagram of an impedance varying part 40. In the presentspecification and drawings, constituent elements having substantiallythe same functions and structures are denoted by the same referencenumerals and symbols, and repeated description thereof will be omitted.

As shown in FIG. 1, the plasma etching apparatus 1 includes a processvessel 2 in, for example, a substantially cylindrical shape. An innerwall surface of the process vessel 2 is covered by a protective film of,for example, alumina. The process vessel 2 is electrically grounded.

For example, in a center bottom portion in the process vessel 2, acolumnar electrode support table 11 is provided via an insulation plate10. On the electrode support table 11, a lower electrode 12 as aradio-frequency electrode serving also as a mounting table for placing asubstrate W thereon is provided. For example, a center portion of anupper surface of the lower electrode 12 protrudes in a columnar shape,and the substrate (semiconductor wafer) W is held on this protrudingportion 12 a. A ring-shaped focus ring 13 made of quartz is providedaround a periphery of the protruding portion 12 a of the lower electrode12.

In a ceiling portion facing the lower electrode 12 in the process vessel2, an upper electrode 20 in, for example, a substantially disk shape isattached so as to make a pair with the lower electrode 12. In a contactportion between the upper electrode 20 and a ceiling wall portion of theprocess vessel 2, a ring-shaped insulator 21 is interposed toelectrically insulate the upper electrode 20 from the ceiling wallportion of the process vessel 2.

A first radio-frequency line 27 supplying a radio-frequency power forplasma generation from a first radio-frequency power source 26 via amatching circuit 25 is electrically connected to the upper electrode 20.This first radio-frequency power source 26 generates, for example, a 60MHz radio-frequency power and supplies the radio-frequency power forplasma generation to the upper electrode 20.

For example, a large number of gas ejecting holes 30 are formed in alower surface of the upper electrode 20. The gas ejecting holes 30communicate with a gas supply source 32 via a gas supply pipe 31connected to an upper surface of the upper electrode 20. The gas supplysource 32 stores a process gas for etching. The process gas introducedfrom the gas supply source 32 into the upper electrode 20 through thegas supply pipe 31 is supplied into the process vessel 2 through theplurality of gas ejecting holes 30.

Further, on a center portion of the lower surface of the upper electrode20, a chemical component emitting member 33 which is a feature of thepresent invention is provided in an exposed state in the process vessel2. This chemical component emitting member 33 is attached in electricalcontinuity to the upper electrode 20, and the chemical componentemitting member 33 and the upper electrode 20 are equal in potential. Aswill be described later, when plasma P is generated in the processvessel 2 by supply of the radio-frequency power to the upper electrode20 and the lower electrode 12, ions in the plasma P are made to enterthe chemical component emitting member 33, thereby causing the chemicalcomponent emitting member 33 to emit a component necessary forprocessing the semiconductor wafer W into the process vessel 2.

A material of the chemical component emitting member 33 can be, forexample, SiO₂, though differing depending on a component to be emittedinto the process vessel 2. The chemical component emitting member 33thus made of SiO₂ can emit oxygen as a component necessary forprocessing the semiconductor wafer W into the process vessel 2, when theions in the plasma P enter the chemical component emitting member 33.

Alternatively, the chemical component emitting member 33 can be made of,for example, fluorocarbon resin. The chemical component emitting member33 thus made of fluorocarbon resin can emit fluorine as a componentnecessary for processing the semiconductor wafer W into the processvessel 2, when ions in the plasma P enter the chemical componentemitting member 33.

The chemical component emitting member 33 of the embodiment shown inFIG. 1 is attached to cover the center portion of the lower surface ofthe upper electrode 20. However, holes for passing the process gastherethrough are formed in the chemical component emitting member 33, incorrespondence to the gas ejecting holes 30 formed in the lower surfaceof the upper electrode 20. Therefore, the process gas introduced intothe upper electrode 20 from the gas supply source 32 is smoothlysupplied into the process vessel 2 through the plurality of gas ejectingholes 30 without being obstructed by the chemical component emittingmember 33.

Further, an impedance varying circuit 41 including an impedance varyingpart 40 varying impedance on the chemical component emitting member 33side of the plasma P generated in the process vessel 2 to frequency of asecond radio-frequency power source 51 is connected to a positionbetween the upper electrode 20 and the matching circuit 25 in theaforesaid radio-frequency line 27. Note that in this embodiment, thechemical component emitting member 33 and the upper electrode 20 are inelectrical continuity to each other and are equal in potential, asdescribed above. Therefore, in this embodiment, the impedance varyingcircuit 41 is connected to the first radio-frequency line 27 forsupplying the radio-frequency power to the upper electrode 20 from thefirst radio-frequency power source 26, so that the impedance varyingpart 40 can vary the impedance on the chemical component emitting member33 side of the plasma P generated in the process vessel 2 (equal toimpedance on the upper electrode 20 side) to frequency of the firstradio-frequency power source 26.

As shown in FIG. 2, the impedance varying part 40 is included in theimpedance circuit 41 connecting the first radio-frequency line 27 andthe ground side and is composed of a fixed coil 42 with inductance of,for example, about 200 nH and a variable capacitor 43 which are seriallyconnected. By varying capacitance of the variable capacitor 43 in theimpedance varying part 40, it is possible to appropriately vary theimpedance on the chemical component emitting member 33 side of theplasma P generated in the process vessel 2 to frequency of the secondradio-frequency power source 51.

A second radio-frequency line 52 for supplying a radio-frequency powerfor bias from the second radio-frequency power source 51 via a matchingcircuit 50 is electrically connected to the lower electrode 12. Thissecond radio-frequency power source 51 generates a radio-frequency powerwith a frequency lower than that of the first radio-frequency powersource 26, for example, a 13.56 MHz radio-frequency power, and suppliesthe radio-frequency power for bias to the lower electrode 12.Incidentally, the plasma P is sometimes generated in the process vessel2 also by this second radio-frequency power source 51.

As shown in FIG. 1, an exhaust pipe 60 connected to an exhaust mechanism(not shown) is connected to a lower portion of the process vessel 2. Byvacuuming the inside of the process vessel 2 through the exhaust pipe60, it is possible to reduce the pressure inside the process vessel 2 toa predetermined pressure.

Next, the operation of the plasma etching apparatus 1 as constructedabove will be described.

To perform plasma etching in this plasma etching apparatus 1, first, thesubstrate W is carried into the process vessel 2 to be placed on thelower electrode 12 as shown in FIG. 1. Then, the inside of the processvessel 2 is exhausted through the exhaust pipe 60 to be reduced inpressure, and further a predetermined process gas supplied from the gassupply source 32 is supplied into the process vessel 2 through the gasejecting holes 30. Further, the first radio-frequency power source 26supplies the radio-frequency power for plasma generation of, forexample, 60 MHz to the upper electrode 20. Further, the secondradio-frequency power source 51 supplies the radio-frequency power forbias of, for example, 13.56 MHz to the lower electrode 12.

Consequently, the radio-frequency power is applied between the lowerelectrode 12 and the upper electrode 20 and the plasma P is generatedbetween the lower electrode 12 and the upper electrode 20 in the processvessel 2. By this plasma P, active species, ions, and so on aregenerated from the process gas, so that a surface film of thesemiconductor wafer W placed on the lower electrode 12 is etched. Afterthe etching for a predetermined time, the supply of the radio-frequencypowers to the upper electrode 20 and the lower electrode 12 and thesupply of the process gas into the process vessel 2 are stopped, thewafer W is carried out of the process vessel 2, and a series of theplasma etching processes is finished.

Here, during the above plasma etching, the capacitance of the variablecapacitor 43 is adjusted in the above-described impedance varying part40 connected to the chemical component emitting member 33, whereby theimpedance on the chemical component emitting member 33 side (upperelectrode 20 side) of the plasma P is changed so as to resonate thefrequency of the second radio-frequency power source 51.

The impedance on the chemical component emitting member 33 side of theplasma P is thus changed, so that the ions in the plasma P are made toenter the chemical component emitting member 33. Consequently, thechemical component emitting member 33 can be caused to emit a componentnecessary for processing the semiconductor wafer W into the processvessel 2.

In this case, appropriately selecting a material of the chemicalcomponent emitting member 33 can change the component which is emittedinto the process vessel 2 from the chemical component emitting member 33by the entrance of the ions. As an example, in a case where a Sisubstrate as the semiconductor wafer W is etched, SiO₂ is used as thematerial of the chemical component emitting member 33. This enables thechemical component emitting member 33 to emit oxygen into the processvessel 2 when the ions in the plasma P enter the chemical componentemitting member 33.

Here, with reference to FIGS. 3( a), 3(b), a case where O₂ and SF6 orHBr are used as the process gas and the Si substrate as thesemiconductor wafer W is etched to form a hole 70 will be described. Bymaking the ions in the plasma P enter the chemical component emittingmember 33 made of SiO₂ to cause the chemical component emitting member33 to emit oxygen into the process vessel 2, it is possible to supplysufficient oxygen into the process vessel 2. Consequently, as shown inFIG. 3( a), oxygen in the process vessel 2 reacts with Si, so that a Sioxide film (SiO₂) 71 is formed on a sidewall surface of the hole 70formed by the etching. The oxide film 71 protects the sidewall surfaceof the hole 70, which makes it possible to etch a surface of thesemiconductor wafer W with high vertical anisotropy.

On the other hand, if oxygen is not sufficiently supplied into theprocess vessel 2, the sidewall surface of the hole 70 is not protected,resulting in isotropic etching as shown in FIG. 3( b). In such a case,the hole 70 formed in the surface of the semiconductor wafer W has abowing shape.

Alternatively, for example, in a case where an oxide film (SiO₂) formedon the surface of a Si substrate as the semiconductor wafer W is etched,fluorocarbon resin, for instance, is used as the material of thechemical component emitting member 33. Consequently, when the ions inthe plasma P enter the chemical component emitting member 33, thechemical component emitting member 33 emits fluorine indispensable foretching the oxide film into the process vessel 2, which can increaseetching rate.

According to the plasma etching apparatus 1 of this embodiment, byappropriately selecting the material of the chemical component emittingmember 33 disposed in an exposed state in the process vessel 2, it ispossible to cause the chemical component emitting member 33 to emit thecomponent necessary for processing the semiconductor wafer W when theions in the plasma P are made to enter the chemical component emittingmember 33. Consequently, anisotropy of the etching can be enhanced andthe etching rate can be also increased.

In this case, for example, concentration of the process gas or the iongeneration state in the process vessel 2 is monitored, and based on themonitoring result, the impedance on the chemical component emittingmember 33 side of the plasma P generated in the process vessel 2 to thefrequency of the second radio-frequency power source 51 is varied toadjust an incident amount of the ions entering the chemical componentemitting member 3 from the plasma P. Consequently, it is possible toeasily control an emission amount of the component such as oxygen orfluorine influencing the plasma processing, which is emitted into theprocess vessel 2 from the chemical component emitting member 33.

Hitherto, an example of a preferred embodiment of the present inventionhas been described, but the present invention is not limited to the formexemplified here. It is obvious that those skilled in the art couldreach various modified examples or corrected examples within a range ofthe spirit described in the claims, and it should be naturallyunderstood that these examples also belong to the technical scope of thepresent invention. For example, in FIG. 2, the case is described wherethe serial circuit of the variable capacitor 43 and the fixed coil 42 isused as the impedance varying part 40, but the impedance varying part 40is not limited to this and may be any circuit, providing that it canvary the impedance on the chemical component emitting member 33 side ofthe plasma P to the frequency of the second radio-frequency power source51.

FIG. 4 is a circuit diagram showing another structure of the impedancevarying part 40. The impedance varying part 40 shown in FIG. 4 hascircuitry in which a fixed capacitor 75, a fixed coil 76, and a variablecapacitor 77 are serially connected and a fixed coil 78 is connected inparallel to the variable capacitor 77, in the impedance varying circuit41 connecting the first radio-frequency line 27 and the ground side.

The impedance varying part 40 shown in FIG. 4 can also easily vary theimpedance on the chemical component emitting member 33 side of theplasma P to the frequency of the second radio-frequency power source 51,by varying the capacitance of the variable capacitor 77. Further,connecting the fixed coil 78 in parallel to the variable capacitor 77facilitates fine adjustment. Further, providing the fixed capacitor 75makes it possible to shift radio-frequency voltage flowing to the groundside from the impedance varying circuit 41, which contributes to theprotection of the impedance varying part 40.

In FIG. 1, the case is described where the chemical component emittingmember 33 is disposed on the lower surface of the upper electrode 20,but this is not restrictive, but the chemical component emitting membermay be disposed at any place exposed to the plasma P generated in theprocess vessel 2. FIG. 5 shows an example where the focus ring 13disposed around the periphery of the lower electrode is used as thechemical component emitting member. In this case, the impedance varyingcircuit 41 including the impedance varying part 40 is connected to thefocus ring 13, thereby varying the impedance on the focus ring 13(chemical component emitting member) side of the plasma P generated inthe process vessel 2 to frequency of the first radio-frequency powersource 26 or the second radio-frequency power source 51.

According to the example shown in FIG. 5, by making the ions in theplasma P enter the focus ring 13, it is possible to cause the focus ring13 to emit the component such as oxygen or fluorine necessary forprocessing the semiconductor wafer W into the process vessel 2. In thismanner, a member (focus ring 13) originally provided in the processvessel 2 for other purpose may be used as the chemical componentemitting member. Needless to say, a member other than the focus ring 13may be used.

FIG. 6 shows an example where a cylindrical chemical component emittingmember 80 is disposed to surround the plasma P generated in the processvessel 2. In this example, the chemical component emitting member 80 isattached to the ceiling portion of the process vessel 2 via aninsulating member 81. Further, the impedance varying circuit 41including the impedance varying part 40 is connected to the chemicalcomponent emitting member 80, thereby varying impedance on the chemicalcomponent emitting member 80 side of the plasma P generated in theprocess vessel 2 to frequency of the first radio-frequency power source26 or the second radio-frequency power source 51.

According to the example shown in FIG. 6, by making the ions in theplasma P enter the chemical component emitting member 80 surrounding theplasma P, it is possible to cause the chemical component emitting member80 to emit the component such as oxygen or fluorine necessary forprocessing the semiconductor wafer W from the plasma P into the processvessel 2.

Incidentally, for example, when the semiconductor wafer W is etched,there sometimes occurs such a situation that etching rate E/R is higherin the center of the semiconductor wafer W and etching rate E/R is lowerin a peripheral edge portion of the semiconductor wafer W, as shown inFIG. 7. In such a case, according to the example shown in FIG. 5 and theexample shown in FIG. 6, the component such as oxygen or fluorine isemitted from the focus ring 13 or the chemical component emitting member80 disposed around the plasma P, thereby increasing the etching rate E/Rin the peripheral edge portion of the semiconductor wafer W, so thatin-plane processing uniformity can be enhanced.

On the other hand, according to the example previously described withreference to FIG. 1, the chemical component emitting member 33 disposedon the center of the lower surface of the upper electrode 20 is causedto emit the component such as oxygen or fluorine. For example, in a casewhere the semiconductor wafer W is etched, there may be a case where theetching rate E/R is lower in the center of the semiconductor wafer W andthe etching rate E/R is higher in the peripheral edge portion of thesemiconductor wafer W (a case reverse to that shown in FIG. 7). In sucha case, the component such as oxygen or fluorine is emitted from thechemical component emitting member 33 provided on the center of thelower surface of the upper electrode 20 as shown in FIG. 1, therebyincreasing the etching rate E/R in the center portion of thesemiconductor wafer W, so that in-plane uniformity of the processing canbe enhanced.

For example, as shown in FIG. 8, sensors 90, 91 detecting emissionintensity (radical density) of the plasma P in the process vessel 2 aremounted in a center portion and a peripheral edge portion of the ceilingportion of the process vessel 2. The emission intensities in the centerportion and the peripheral edge portion of the semiconductor wafer W areinputted from these sensors 90, 91 to a computing device 93 via aspectroscope 92. The computing device 93 computes an adjustment angle ofthe variable capacitor 43 of the impedance varying part 40 which is tobe controlled, based on a ratio of the emission intensities in thecenter portion and the peripheral portion of the semiconductor wafer W.While the variable capacitor 43 is controlled based on thus computedadjustment angle, the ions in the plasma P are made to enter thechemical component emitting member 33, which can equalize the emissionintensities (radical densities) in the center portion and the peripheraledge portion of the semiconductor wafer W. Consequently, uniform plasmaprocessing is enabled.

Incidentally, the chemical component emitting member 33, shown in FIG.1, disposed on the lower surface of the upper electrode 20, the chemicalcomponent emitting member, shown in FIG. 5, constituted by the focusring 13, and the chemical component emitting member 80, shown in FIG. 6,disposed around the plasma P may be appropriately combined.

The above embodiments have described the examples where theradio-frequency power sources 26, 51 are connected to the upperelectrode 20 and the lower electrode 12 respectively, but this is notrestrictive. The present invention is of course applicable to a casewhere a radio-frequency power source is connected to only one of theelectrodes. Further, in the above-descried embodiments, the presentinvention is applied to the plasma etching apparatus 1, but the presentinvention is also applicable to a plasma processing apparatus forperforming substrate processing other than etching, for example, forperforming film formation. Further, the substrate processed in theplasma processing apparatus of the present invention may be any of asemiconductor wafer, an organic EL substrate, a substrate for FPD (flatpanel display), and the like.

1. A plasma processing apparatus in which a radio-frequency power from aradio-frequency power source is supplied to an electrode disposed in aprocess vessel, to thereby generate, in the process vessel, plasma withwhich a substrate is processed, wherein a chemical component emittingmember which is caused to emit a chemical component necessary forprocessing the substrate into the process vessel by entrance of ions inthe plasma generated in the process vessel is provided in the processvessel in an exposed state, and wherein an impedance varying circuitvarying impedance on said chemical component emitting member side of theplasma generated in the process vessel to frequency of theradio-frequency power source is connected to said chemical componentemitting member.
 2. The plasma processing apparatus according to claim1, wherein said chemical component emitting member is disposed on alower surface of the electrode.
 3. The plasma processing apparatusaccording to claim 1, wherein said chemical component emitting member isa focus ring provided around a periphery of the electrode.
 4. The plasmaprocessing apparatus according to claim 1, wherein said chemicalcomponent emitting member is disposed around the plasma generated in theprocess vessel.
 5. The plasma processing apparatus according to claim 1,wherein the chemical component necessary for processing the substrate isoxygen.
 6. The plasma processing apparatus according to claim 5, whereinsaid chemical component emitting member is made of SiO₂.
 7. The plasmaprocessing apparatus according to claim 1, wherein the chemicalcomponent necessary for processing the substrate is fluorine.
 8. Theplasma processing apparatus according to claim 7, wherein said chemicalcomponent emitting member is made of fluorocarbon resin.